有序氧化矽、氯化鈉單一原子層在矽晶面上的成長過程

The Formation Process of Single Ordered Atomic Silicon Oxide and NaCl Layer on the Si(100) Surface

張展源(Chang, Chan Yuen)

指導教授 ： 林登松

國立清華大學/理學院/物理學系/博士(2014年)

https://doi.org/10.6843/NTHU.2014.00005

摘要

在過去幾十年來，超薄絕緣層在矽(100)面上的成長無論是基礎科學領域或是半導體工業製程方面來說都是非常重要的課題。其中，隨著晶片製持續微縮下，絕緣層與矽晶面的界面品質變得更重要且足以進一步影響整體元件的特性。因此，如果我們可以建立一個平台，讓上面的絕緣層及下面的矽晶面做更好結合，元件特性將能有效提升。在本論文裡，我們在矽(100)面上創造了兩種非常不同的平台層。
第一種是單層有序的氧化矽結構。藉有氧原子直接曝在表面的方式，迥於之前以氧分子做反應單元的方式，單一層且有序的氧化矽結構可以在室溫的情況下被做出來。關於氧原子在矽(100)面上的詳細反應過程也會做討論。此外，氧化矽從晶相轉換到非晶相結構的中間過程也可清楚的看到。根據我們提出的模型，從光電子能譜及掃描穿隧式電子顯微鏡得到的實驗數據在量化分析上是一致的。
至於第二個主題，藉由室溫下連續半反應的過程，單一異質層的氯化鈉成功長在矽(100)面上。第一道半反應是先把氯氣曝在表面上，進而形成氯原子吸附在表面的結構，其氯原子間的距離非常接近氯化鈉(100)表面上氯原子間的距離。藉由掃描穿隧式電子顯微鏡及光電子能譜技術的運用，在第二道半反應的製程中-鈉原子的蒸鍍，我們發現鈉原子會經由叢集、區塊的階段，把原本吸附在表面的氯原子轉化成單一層波浪狀的氯化鈉結構。新長出的單層氯化鈉以類似地毯的方式越過表面的階梯區域且進而覆蓋整個表面。在此氯化鈉層下方，矽表面的原子和電子結構與初始狀態且具雙原子單元之起伏特徵的矽表面非常接近。綜合所有的研究結果來看，此單一氯化鈉原子層以非常微弱的方式依附在此共價鍵結的表面上。

關鍵字

單一原子層氧化矽 ； 單一原子層氯化鈉 ； 異質介面成長 ； 獨立懸空鍵 ； 掃描穿隧式電子顯微術

並列摘要

The ultrathin insulator growing on the Si(100) surface is a very important issue for the past decades regardless of the basic scientific field or semiconductor industry manufacture. In which, the quality of interface between the insulating film and silicon surface becomes a more important factor for affecting overall device performance by latest device size’s shrinking. Therefore, if we can construct one platform which can better combine above insulating film and below silicon surface, the device performance will promote effectively. In this thesis, we establish two very different kinds of platform layers on Si(100) surface.
The first one is single ordered atomic silicon oxide layer. By exposing oxygen atomic atoms rather than traditional method of oxygen molecular reactants, single monolayer and well-ordered silicon oxide layer can be created at room temperature. The detailed reaction process about oxygen atomic reactants reacting with Si(100) surface will be discussed. Besides, the process from the crystal to amorphous silicon oxide is also revealed clearly. The data acquiring from the XPS and STM techniques also can coincide very well on the basis of our proposed model.
As for the second topic, an atomic layer of stoichiometric NaCl was formed on a covalent Si(100) surface after two successive half-reactions at room temperature. The first half-reaction due to Cl2 exposure generates a square array of Cl adatoms with a distance close to that in a NaCl(100) surface plane. By utilizing scanning tunneling microscopy(STM) and core-level photoemission spectroscopy, it was found that progressive deposition of Na in the second-half reaction results in clusters, patches, and eventually turns the Cl-adlayer into a single-terrace, wavy NaCl layer at one monolayer Na coverage. The grown NaCl monolayer rolls over atomic steps like a carpet and covers the entire surface. The atomic and electronic structure of the topmost Si layer underneath the NaCl layer resembles that of the initial silicon surface layer with buckled dimers. Results of the comprehensive investigation together suggest that an ionic NaCl monolayer is very weakly bonded to the covalent substrate and appears nearly free standing.

並列關鍵字

Single atomic silicon oxide layer ； Single atomic NaCl layer ； Heterogeneous growth ； Isolated single dangling bond ； Scanning tunneling microscope

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